1. Field of the Invention
The present invention relates to the field of the transport and storage of planar articles, in particular within the framework of print finishing. It relates to an apparatus for the intermediate storage of planar articles which can be spooled in an imbricated stream arrangement, according to the preamble to claim 1. It further relates to a method for operating such an apparatus.
2. Discussion of Related Art
In print finishing, also known as print further processing, specifically, a variety of print products, printed sheets, supplements, flyers, etc., once they have been printed, must initially be temporarily stored, so as then to be retrieved from store for the assembly of finished print products, for instance newspapers provided with supplements.
For intermediate storage in a space-saving, flexibly manageable and fast-working manner, winding stations in which the print products arriving in an imbricated stream are spooled onto a winding core for intermediate storage, with the formation of a reel, and are unspooled again for retrieval from store, have proved their worth. Once the reel of print products which is formed in a winding station has reached a maximum diameter, the storage capacity of this winding station is exhausted. In order to accommodate further print products, either a new reel has to be started in the same winding station, or the incoming imbricated stream of print products must be diverted to another winding station. Conversely, if the reel of a winding station is fully unspooled when retrieved from store, either the empty reel must be exchanged for a full reel in the same winding station, or a switch is made to another winding station holding a full reel.
In order to be able to make optimal use of such winding stations as temporary stores, it should be possible, at the same time and without mutual disturbance, to use first winding stations to enter print products into store, whilst print products are retrieved from store from second winding stations, and vice versa.
Printed publication DE 33 04 219 discloses an apparatus for stacking printed sheets, in which a high stacking capacity can be obtained in a comparatively tight space, wherein there are provided 12 buffer and stacking lines, arranged side by side in parallel, which are fed partial imbricated streams via a common feeder conveying line, or from which partial imbricated streams can be transported away via a common evacuation line. In each of the 12 buffer and stacking lines are arranged, on opposite sides of the centrally traversing feeder conveying line and evacuation line, two winding stations, of which one serves for the spooling of the partial imbricated streams and the other for the rewinding of the partial imbricated streams in order to have the desired stream position in the imbricated stream when retrieved from store. The selection of the individual buffer and stacking lines is realized by associated points switch arrangements, which are fixedly disposed on the feeder conveying line and evacuation line and with which the entry into and retrieval from store, and the transverse connection between opposite winding stations, is switched. A drawback with this stacking apparatus is, inter alia, the cost and spatial requirement of the equipment, due to the winding stations which are used in pairs.
Printed publication WO 94/02398 discloses a device for the processing of print products, in which upstream of a processing station is disposed a product store having two storage units for the spooling of print products supplied as an imbricated stream. The print products make their way into the storage units via a feed path, the feed path having a curved feed portion. The retrieval from the individual storage units is realized via a straight store retrieval line up to the processing station. For the appropriate alteration of the conveying paths, a points switch can be used. Here too, increased equipment outlay is necessary, since the transitions between supply lines and discharge lines, as well as the connecting lines leading to the storage units, are to some extent hard-wired.
Printed publication DE 196 00 809 discloses a method for storing planar articles, in which a first part of the articles generated in an imbricated stream formation is spooled into a first reel and at least a further part of the articles into a further reel assigned to the first reel, or unspooled therefrom, wherein the articles are spooled synchronously onto all reels with the same orientation, or unspooled synchronously from all reels with the same orientation. For the implementation of the method, a spooling station, a temporary store and a finishing station, between which the reels are transported to and fro with transport vehicles, are arranged spatially separate from one another. This gives rise to a greater spatial requirement and a flexible, yet comparatively complex process technology.
Printed publication EP 0 229 888 discloses an apparatus for the storage of print products generated in imbricated stream formation, in which, at a common supporting column, one above the other, are arranged a number of similar winding units, which can be turned independently from one another. For the feeding of the print products to be spooled onto the winding cores, a conveyor is present, which conveyor has a height-adjustable outlet region. The spooling units can be individually loaded with print products and also individually emptied again. In this configuration, only ever one winding unit can either be loaded or unloaded. A combined, flexible operation is not possible.
Printed publication EP 0 272 398 discloses a method and a device for transferring printed articles generated in at least one continuous stream to the supply lines of at least two processing stations. In order that the division of the generated stream can be performed as continuously as possible and can be optimally matched to the requirements of the processing stations, the stream is conducted in such a way that it crosses the supply lines, wherein at the intersections the stream is fed at least periodically to a store, whilst at the same intersection printed articles are simultaneously transferred from the store via a transfer point to the supply point. As the storage devices, a twin-reel stand, which respectively supports two reels, is present in the region of each intersection. The reel stands are displaceable along the supply line in order that respectively one of the reels can be aligned to one of the used conveyors, with the other reel being aligned to one of the transfer points at the intersection in question.
Common to the solutions known from the prior art is the fact that, in order to achieve a flexible intermediate storage, they require a comparatively large outlay on equipment, which is at the same time linked to a not inconsiderable spatial requirement.